JP6549021B2 - Endoscope system and operation method of measurement apparatus - Google Patents

Description

  The present invention relates to a measurement apparatus, an endoscope system, and a measurement method, and more particularly to a measurement apparatus, an endoscope system, and a measurement method for measuring an object using laser light.

  In the field of measurement devices such as endoscopes, laser light is used to measure the distance to an object or to calculate shape information of an object. For example, in Patent Document 1, a laser beam is irradiated as a spot-like measurement light to an object to be observed, and it is measured at which point the spot light is located on the object to be observed. A measuring endoscope apparatus is described which calculates two-dimensional information or three-dimensional information of an object to be observed by comparing it with the reference value.

  Further, Patent Document 2 describes an endoscope system that performs stereo measurement using a grid-like mask pattern. In this technique, a mask means as a projection means for irradiating a lattice pattern with a laser is provided at the tip of a laser guide for guiding a laser beam, and the lattice pattern is irradiated with a laser to a measurement object. Then, this grid pattern is used for matching of left and right images to perform stereo measurement.

  Furthermore, Patent Document 3 describes an endoscope apparatus that measures an object using a fringe image in which a light and dark pattern is projected on the object.

Patent No. 3853954 Patent 4358494 gazette JP 2012-239834 A

  In order to calculate the shape information of the object to be observed by the technique described in Patent Document 1, it is necessary to accurately know the size of the spot light on the object to be observed. However, if the distance to the object to be observed changes, or if the surface condition of the object to be observed or the exposure condition of the imaging system changes, the size of the spot light will be observed differently, such a change in conditions It was difficult to make an accurate measurement without relying on it.

  Further, in the technique described in Patent Document 2, since there is no collimator lens between the mask and the laser guide, the mask pattern is projected by the laser light which has been transmitted through the mask and diverged. Therefore, as the distance to the object is increased, the mask pattern is projected to be darker, and the brightness of the mask pattern largely changes depending on the distance, so it is difficult to perform accurate measurement regardless of the distance. . In the technique described in Patent Document 3, the mask forms an image only within the depth of field of the lens because the mask pattern is projected by the lens. In order to increase the depth of field, it is necessary to increase the f-number of the lens, which requires a high-intensity illumination light source.

  As described above, it is difficult to perform accurate measurement regardless of the distance to the object and the exposure condition in the conventional technique.

  The present invention has been made in view of such circumstances, and provides a measuring device, an endoscope system, and a measuring method capable of performing accurate measurement even if the distance to an object or the exposure condition changes. The purpose is

  In order to achieve the above-mentioned object, the measuring device according to the first aspect of the present invention comprises a laser light source for emitting a laser beam, a collimator for emitting the emitted laser beam as parallel light beams, and a collimator. Imaging based on a diffraction grating that generates a plurality of spot lights from a light beam, an imaging unit that acquires images of a plurality of diffraction spots formed on a subject by the plurality of spot lights via an imaging element, and the acquired images A measurement unit configured to measure an interval of a plurality of diffraction spots on an image forming surface of the element, and a calculation unit configured to calculate a distance to an object based on the intervals of the plurality of measured diffraction spots.

  According to the first aspect, since a plurality of spot lights are formed by the diffraction grating from parallel light beams emitted from the collimator, the size of the spot light does not change depending on the distance to the object. Further, since the distance between the plurality of diffraction spots is measured, even if the size of the spot light changes due to the change of the exposure condition, the measurement accuracy can be maintained by measuring the distance between the diffraction spots. As described above, in the measuring apparatus according to the first aspect, accurate measurement can be performed even if the distance to the object or the exposure condition changes.

  In the measurement apparatus according to the second aspect, in the first aspect, the calculation unit is configured to calculate the distance to the object based on the relationship between the distance between the plurality of diffraction spots on the imaging surface and the object stored in advance. Calculate the distance. The second aspect defines one aspect of a method of calculating the distance to the object from the intervals of a plurality of diffraction spots.

  In the measurement apparatus according to the third aspect, in the second aspect, the relationship stored in advance differs depending on the image heights of the plurality of diffraction spots on the imaging surface. When acquiring images of a plurality of diffraction spots, the distance between the diffraction spots changes depending on the image height of the diffraction spot on the imaging surface (the distance from the center of the imaging surface) depending on the angle of view of the imaging lens. In the aspect, accurate measurement can be performed even in such a case.

  In the measurement apparatus according to the fourth aspect, in the third aspect, in the relation stored in advance, as the image height of the plurality of diffraction spots is higher, the object corresponding to the same interval of the plurality of diffraction spots on the imaging surface The distance to the sample is long. The fourth aspect relates to one of how the relationship between the distance between the diffraction spots (corresponding to the number of pixels of the imaging device) on the imaging plane and the distance to the object differs depending on the image height of the diffraction spots. It defines an aspect.

  In the measurement apparatus according to the fifth aspect, in any one of the first to fourth aspects, the diffraction grating is a diffraction grating that generates a plurality of spot lights having a period in a two-dimensional direction as the plurality of spot lights. is there. According to the fifth aspect, since a plurality of spot lights having a cycle in a two-dimensional direction are generated, it is not necessary to change the direction of the spot light in order to perform measurement in different directions, and measurement can be performed quickly and easily. It can be performed. In the fifth aspect, a single diffraction grating may be used to generate a plurality of spot lights having a period in a two-dimensional direction, or a plurality of diffraction gratings may be combined.

  In the measurement apparatus according to the sixth aspect, in any one of the first to fifth aspects, the imaging device is disposed on a plurality of pixels including a plurality of light receiving elements arranged in a two-dimensional array, and a plurality of pixels And the measurement unit is an image of a pixel in which the color filter of the filter color having the highest sensitivity to the wavelength of the laser light is disposed among the plurality of filter colors. The spacing of the plurality of diffraction spots is measured based on the image generated by the signal. According to the sixth aspect, of the plurality of filter colors of the color filter, the plurality of filters are generated based on the image signal generated by the image signal of the pixel provided with the color filter of the filter color having the highest sensitivity to the wavelength of the laser light. Since the distance between the diffraction spots is measured, it is possible to obtain an image in which the diffraction spots are clear, which enables accurate measurement.

  In the measurement apparatus according to the seventh aspect, in any one of the first to sixth aspects, the calculation unit calculates two-dimensional information or three-dimensional information of the subject based on the calculated distance to the subject . According to the seventh aspect, information such as the two-dimensional or three-dimensional shape or size of the subject can be accurately calculated based on the result of the accurate measurement.

  The measuring apparatus according to the eighth aspect is an optical fiber for guiding laser light from the laser light source to the collimator according to any one of the first to seventh aspects, wherein the optical fiber is for transmitting the laser light in a single transverse mode. Prepare. According to the eighth aspect, since the optical fiber propagates the laser light in the single transverse mode, it is possible to form a sharp diffraction spot with a small diameter, whereby accurate measurement can be performed.

  In the measurement apparatus according to the ninth aspect, in any one of the first to eighth aspects, the collimator is a graded index lens in which the refractive index is the highest at the optical axis and decreases toward the radially outer side. According to the ninth aspect, since the collimator is a graded index lens (graded index lens), the module for emitting laser light can be miniaturized (reduced in diameter).

  In order to achieve the above-mentioned object, an endoscope system according to a tenth aspect of the present invention includes the measurement device according to any one of the first to ninth aspects. The endoscope system according to the tenth aspect includes the measurement device according to any one of the first to ninth aspects, so that accurate measurement is performed even if the distance to the object or the exposure condition changes. be able to.

  An endoscope system according to an eleventh aspect is the insertion part inserted into the subject according to the tenth aspect, wherein the distal end hard portion and the bending portion connected to the proximal end side of the distal end hard portion are included. An endoscope having an insertion part having a flexible part connected to the base end side of the bending part, and an operation part connected to the base end side of the insertion part; a diffraction grating; and a plurality of diffraction spots An imaging lens for forming an optical image on an imaging element is provided on the end surface of the distal end rigid portion. An eleventh aspect defines one aspect of the configuration of the distal end rigid portion of the endoscope.

  In an endoscope system according to a twelfth aspect, in the eleventh aspect, a module including an assembly of a diffraction grating and a collimator is provided in the distal end rigid portion. The twelfth aspect defines one aspect of the arrangement of a module including a conjugate of a diffraction grating and a collimator.

  The endoscope system according to a thirteenth aspect is the endoscope system according to the twelfth aspect, wherein a conduit communicating with the forceps port opened at the distal end rigid portion is provided in the insertion portion, and the module is inserted through the conduit so as to be insertable and removable . According to the thirteenth aspect, since the module can be inserted using the pipeline communicating with the forceps port, the device can be miniaturized.

  The endoscope system according to a fourteenth aspect includes, in any one of the tenth to thirteenth aspects, an illumination light source that emits illumination light, and a control unit that controls the illuminance of the illumination light. In the measurement mode in which the imaging unit acquires images of a plurality of diffraction spots by the imaging unit, the illumination light is irradiated to the subject to lower the illuminance of the illumination light than in the normal observation mode in which the subject is observed. If the illuminance of the illumination light at the time of imaging the diffraction spot is too high, the diffraction spot may become unclear in the obtained image and affect the measurement accuracy, but in the thirteenth aspect, the control unit In the measurement mode for imaging a plurality of diffraction spots, the illuminance of the illumination light is lower than that in the normal observation mode in which the subject is irradiated with illumination light to observe the subject, so that an image with a sharp diffraction spot can be captured. This makes it possible to make an accurate measurement. In the thirteenth aspect, how much the illuminance of the illumination light is lowered when imaging the diffraction spot may be set according to the type, size, brightness, etc. of the subject, and the illumination light is turned off as necessary. You may

  In order to achieve the above-mentioned object, according to a fifteenth aspect of the present invention, there is provided a measurement method comprising: a laser light source for emitting a laser beam; a collimator for emitting the emitted laser beam as parallel light beams; A measurement method using a measurement apparatus including a diffraction grating that generates a plurality of spot lights from a light flux, and an imaging step of acquiring images of a plurality of diffraction spots formed on a subject by the plurality of spot lights; The measurement process of measuring the space | interval of several diffraction spots based on the acquired image, and the calculation process which calculates the distance to a test object based on the space | interval of several diffraction spots measured. According to the fifteenth aspect, as in the first aspect, accurate measurement can be performed even if the distance to the object or the exposure condition changes.

  As described above, according to the measuring device, the endoscope system, and the measuring method of the present invention, accurate measurement can be performed even if the distance to the object or the exposure condition changes.

FIG. 1 is a diagram showing an entire configuration of an endoscope system according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the endoscope system according to the first embodiment of the present invention. FIG. 3 is a view showing the configuration of the distal end side end face of the distal end hard portion. FIG. 4 is a diagram showing the configuration of the laser module. FIG. 5 is a diagram showing a two-dimensional diffraction grating. FIG. 6 is a cross-sectional view showing a laser light source module. FIG. 7 is a view showing a state in which the insertion portion of the endoscope is inserted into a subject. FIG. 8 is a diagram showing a two-dimensional diffraction spot. FIG. 9 is a flowchart showing the flow of measurement processing. FIG. 10 is a view showing how a two-dimensional diffraction spot is formed on a subject. FIG. 11 is a diagram showing the relationship between the wavelength and the sensitivity of the color filter. FIG. 12 is a diagram showing the direction and distance of a diffraction spot. FIG. 13 is a view showing a one-dimensional diffraction grating in the second embodiment of the present invention. FIG. 14 is a view showing a laser module according to a second embodiment of the present invention. FIG. 15 is a view showing a one-dimensional diffraction spot in the second embodiment of the present invention. FIG. 16 is a view showing how a one-dimensional diffraction spot is formed on the object in the second embodiment of the present invention. FIG. 17 is a view showing a laser module in the third embodiment of the present invention. FIG. 18 is a view showing a diffraction grating in the third embodiment of the present invention. FIG. 19 is another view showing the diffraction grating in the third embodiment of the present invention. FIG. 20 is a view showing a laser module in the fourth embodiment of the present invention.

  Hereinafter, an embodiment of a measurement device, an endoscope system, and a measurement method according to the present invention will be described in detail with reference to the attached drawings.

First Embodiment
FIG. 1 is an external view showing an endoscope system 10 (measuring device, endoscope system) according to the first embodiment, and FIG. 2 is a block diagram showing a main part configuration of the endoscope system 10 . As shown in FIGS. 1 and 2, the endoscope system 10 includes an endoscope apparatus 100 including an endoscope main body 110 (endoscope), an endoscope processor 200, a light source device 300, and a monitor 400. It contains.

<Configuration of Endoscope Body>
The endoscope main body 110 includes a hand operation unit 102 and an insertion unit 104 connected to the hand operation unit 102. The operator holds and operates the hand operation unit 102, inserts the insertion unit 104 into the body of the subject, and performs observation. The insertion portion 104 is composed of a soft portion 112, a bending portion 114, and a distal end hard portion 116 in order from the hand operation portion 102 side. The distal end rigid portion 116 is provided with an imaging optical system 130 (imaging unit), an illumination unit 123, a forceps port 126, a laser module 500, and the like (see FIGS. 1 to 3A, 4).

  At the time of observation and treatment, either or both of visible light and infrared light can be emitted from the illumination lenses 123A and 123B of the illumination unit 123 by the operation of the operation unit 208 (see FIG. 2). Further, cleaning water is released from a water supply nozzle (not shown) by the operation of the operation unit 208, and the imaging lens 132 of the imaging optical system 130 and the illumination lenses 123A and 123B can be cleaned. A conduit (not shown) is in communication with the forceps port 126 opened at the distal end hard portion 116, and a treatment tool (not shown) for tumor extraction and resection is inserted through the conduit, appropriately advanced and retracted, and the subject Are able to take necessary measures.

  As shown in FIGS. 1 to 3A, an imaging lens 132 is disposed on the distal end side end face 116A of the distal end hard portion 116, and a CMOS (Complementary MOS) type imaging element is disposed behind the imaging lens 132. A driving circuit 136 and an AFE (Analog Front End) 138 are disposed to output an image signal. The imaging elements 134 are color imaging elements, and are arranged in a matrix (two-dimensional form) in a predetermined pattern arrangement (Bayer's arrangement, G stripe R / G perfect checker, X-Trans (registered trademark) arrangement, honeycomb arrangement, etc.) Of light receiving elements, each of which includes a microlens, a color filter of red (R), green (G), or blue (B) and a photoelectric conversion unit (such as a photodiode). It is. The imaging optical system 130 can also generate a color image from pixel signals of three colors of red, green, and blue, or generates an image from pixel signals of any one or two colors of red, green, and blue. It can also be done.

  Although the case where the imaging device 134 is a CMOS imaging device is described in this embodiment, the imaging device 134 may be a CCD (Charge Coupled Device) type.

  An image of an object and an optical image of a diffraction spot (described later) are imaged on a light receiving surface (imaging surface) of the imaging element 134 by the imaging lens 132 and converted into an electric signal, and is viewed through the signal cable (not shown) It is output to the mirror processor 200 and converted into a video signal. As a result, the observation image and the photographed image of the diffraction spot (see FIG. 10) are displayed on the monitor 400 connected to the endoscope processor 200.

  In addition, illumination lenses 123A (for visible light) and 123B (for infrared light) of the illumination unit 123 are provided adjacent to the imaging lens 132 at the tip end face 116A of the distal end hard portion 116. Behind the illumination lenses 123A and 123B, an emission end of a light guide 170 described later is disposed, and the light guide 170 is inserted into the insertion portion 104, the hand operation portion 102, and the universal cable 106, An entrance end is disposed within the light guide connector 108.

  The laser head 506 of the laser module 500 is further provided on the tip end face 116 A, and a plurality of spot lights are irradiated through the diffraction grating 512. The configuration of the laser module 500 will be described later. In the present embodiment, as shown in FIG. 3A, the case where the laser head 506 is provided separately from the forceps port 126 is described, but in the measuring apparatus and the endoscope system according to the present invention, As shown in FIG. 3 (b), the laser head 506 may be inserted in a removable manner into a conduit (not shown) communicating with the forceps port 126 opened at the distal end rigid portion 116. In this case, it is not necessary to provide a conduit dedicated to the laser head 506, and the conduit communicating with the forceps port 126 can be shared with other treatment tools.

<Configuration of laser module>
As shown in FIGS. 2 and 4, the laser module 500 includes a laser light source module 502 (laser light source), an optical fiber 504, and a laser head 506 (module). The optical fiber 504 is inserted into a ferrule 508 and adhesively bonded, and the end face is polished. A GRIN (graded index) lens 510 (collimator) is attached to the tip end of the ferrule 508, and a diffraction grating 512 is attached to the tip end of the GRIN lens 510 to form a joined body. The ferrule 508 is a member for holding and connecting the optical fiber 504, and a hole for inserting the optical fiber 504 is formed in the central portion in the axial direction (left and right direction in FIG. 4). The ferrule 508, the GRIN lens 510, and the diffraction grating 512 are housed in a housing 509 to constitute a laser head 506.

  The laser module 500 configured as described above is attached to the insertion unit 104. Specifically, as shown in FIG. 2, the laser light source module 502 is provided at the hand operation unit 102, the laser head 506 is provided at the distal end hard portion 116, and the optical fiber 504 emits laser light from the laser light source module 502. The light is guided to the head 506. The laser light source module 502 may be provided in the light source device 300, and the laser light may be guided to the distal end hard portion 116 by the optical fiber 504.

  The laser light source module 502 includes a VLD (Visible Laser Diode) that emits power in the visible wavelength range when supplied with power from a power supply (not shown) and a focusing lens 503 that focuses the laser light emitted from the VLD. It is a pigtail type module (TOSA; Transmitter Optical Sub Assembly) provided (see FIG. 6). The laser light can be emitted as needed by control of the CPU 210, and the laser light is emitted only when distance measurement by spot light irradiation or acquisition of two-dimensional or three-dimensional information of the object is performed, at the time of non-emission It can be used in the same manner as a conventional endoscope.

  In the present embodiment, the laser light emitted from the VLD can be red laser light with a wavelength of 670 nm by the semiconductor laser. However, the wavelength of the laser light in the present invention is not limited to this embodiment. The laser light collected by the collecting lens 503 is guided by the optical fiber 504 to the GRIN lens 510. The optical fiber 504 is an optical fiber for propagating laser light in a single transverse mode, and can form a sharp diffraction spot (see FIGS. 8 and 10) having a small diameter, so that accurate measurement can be performed. A relay connector may be provided in the middle of the optical fiber 504.

  The GRIN lens 510 is a cylindrical graded index lens (radial type) whose refractive index is highest at the optical axis and decreases toward the radially outer side, and parallels laser light guided by the optical fiber 504 and incident thereon It functions as a collimator that emits a light beam. The spread of the light beam emitted from the GRIN lens 510 can be adjusted by adjusting the length of the GRIN lens 510, and for emitting laser light of parallel light flux, (λ / 4) pitch (λ is the wavelength of the laser light) You should do it to the extent.

  A diffraction grating 512 is mounted on the tip side of the GRIN lens 510. In the diffraction grating 512, as shown in FIG. 5 (a) as a front view and FIG. 5 (b) as a side view, the projections 512A are formed with a period P1 in a two-dimensional direction, thereby making a two-dimensional direction A plurality of spot lights having a cycle are generated (see FIGS. 8 and 10) and emitted in the left direction of FIG. The irradiation direction of the spot light is determined depending on the wavelength λ of the laser light and the period P1 of the projection 512A. In the present embodiment, a total of 25 projections are formed at square lattice points, five projections 512A each in the horizontal and vertical directions, and a total of 25 diffraction gratings each having five square projections in the horizontal and vertical directions. Although the case where it is formed into points (see FIGS. 8 and 10) will be described, the number and arrangement of the protrusions formed on the diffraction grating in the present invention are not limited to such an embodiment. The number and arrangement of the protrusions can be determined in consideration of the assumed measurement distance, the size of the object, the measurement accuracy and the like. Further, the shape of the protrusion is not limited to a circle like the protrusion 512A, and may be another shape such as a rectangle.

<Configuration of light source device>
As shown in FIG. 2, the light source device 300 includes a light source 310 for illumination (illumination light source), a diaphragm 330, a condenser lens 340, a light source control unit 350 (control unit), etc. Light or infrared light is incident on the light guide 170. The light source 310 includes a visible light source 310A (illumination light source) and an infrared light source 310B (illumination light source), and can emit one or both of visible light and infrared light. The illuminance of illumination light by the visible light source 310A and the infrared light source 310B is controlled by the light source control unit 350 (control unit), and the illuminance of the illumination light is lowered as needed when imaging a diffraction spot as described later. It is possible to stop the lighting and so on.

  By connecting the light guide connector 108 (see FIG. 1) to the light source device 300, the illumination light emitted from the light source device 300 is transmitted to the illumination lenses 123A and 123B through the light guide 170, and the illumination lens 123A, It irradiates to the observation range from 123B.

<Configuration of Endoscope Processor>
Next, the configuration of the endoscope processor 200 will be described based on FIG. The endoscope processor 200 receives an image signal output from the endoscope apparatus 100 via the image input controller 202, and performs image processing necessary for the image processing unit 204 (measuring unit, calculating unit) to output a video. Output via the unit 206. Thus, the observation image is displayed on the monitor 400. These processes are performed under the control of a CPU (Central Processing Unit; central processing unit) 210 (measuring unit, calculating unit, control unit). In the image processing unit 204, in addition to image processing such as white balance adjustment, switching or superposition display of an image displayed on the monitor 400, electronic zoom processing, display / switching of an image according to the operation mode, specific components from the image signal ( For example, extraction of a luminance signal) is performed. Further, the image processing unit 204 performs measurement of the distance between the diffraction spots, calculation of the distance to the object based on the measured distance, and calculation of two-dimensional information or three-dimensional information of the object based on the calculated distance Later). The memory 212 contains information necessary for processing performed by the CPU 210 and the image processing unit 204, for example, the distance between a plurality of diffraction spots on the imaging surface of the imaging device 134 and the distance to the object And the distance from the subject to the subject are stored in advance.

  The endoscope processor 200 also includes an operation unit 208. The operation unit 208 includes an operation mode setting / switching switch (not shown), a water supply instruction button, and the like, and can operate irradiation of visible light and infrared light.

<Observation by endoscopic device>
FIG. 7 is a view showing a state in which the insertion unit 104 of the endoscope apparatus 100 is inserted into a subject, and shows a state in which an observation image is obtained through the imaging optical system 130. In FIG. 7, the reference symbol IA indicates an imaging range, and the reference symbol tm indicates a tumor (a black and raised portion in FIG. 7).

<Distance to subject and distance between diffraction spots>
FIGS. 8A and 8B are diagrams showing the relationship between the distance to the object and the diffraction spot. FIG. 8A shows the diffraction spot DS1 (distance D1) when the distance to the subject is long, and FIG. 8B shows the diffraction when the distance to the subject is nearer than FIG. 8A. The spots DS1 (interval D2 (<D1)) are shown. Since the spot light emitted from the laser head 506 is emitted at a constant angle, the distance between the diffraction spots DS1 changes according to the distance from the end face of the laser head 506. Therefore, it is possible to measure the distance and to calculate the distance based on this.

  In this embodiment, since spot light is generated from parallel light emitted from the collimator (GRIN lens 510) by the diffraction grating (diffraction grating 512), the spot light corresponding to one protrusion of the diffraction grating is constant according to the principle of light diffraction. It is emitted at an angle of, and the spread of light is small. Therefore, even if the distance to the object changes, the size of the diffraction spot DS1 hardly changes, and even if the distance to the object changes, the luminance of the diffraction spot DS1 hardly changes. Since the distance between the diffraction spots DS1 is measured, measurement accuracy can be maintained by measuring the distance between the diffraction spots DS1 even if the size of the diffraction spots DS1 changes due to a change in exposure conditions. . As described above, in the endoscope system 10 according to the first embodiment, accurate measurement can be performed even if the distance to the object or the exposure condition changes.

<Flow of measurement processing>
Next, the measurement process of the subject by the endoscope system 10 will be described. FIG. 9 is a flowchart showing the flow of measurement processing.

<Imaging of diffraction spot>
First, as shown in FIG. 7, the insertion portion 104 is inserted into the subject, and a plurality of spot lights are irradiated from the laser module 500 to the subject (the portion of the tumor tm), and a plurality of diffraction spots are shown as shown in FIG. Form DS1. Then, an image of the diffraction spot DS1 is acquired by the imaging optical system 130 (imaging unit) (step S100; imaging step). At the time of imaging, the bending portion 114 is appropriately bent vertically and horizontally by operation of the hand operation portion 102 to change the direction of the distal end hard portion 116, and the diffraction spot DS1 is formed on the observation target portion (the portion of the tumor tm in FIG. 10). To be done. In the endoscope system 10, the subject is illuminated by the visible light source 310A or the infrared light source 310B, but the illuminance of illumination light by the visible light source 310A and the infrared light source 310B is controlled by the light source control unit 350 (control unit) In the mode (measurement mode) in which a diffraction spot is imaged by the optical system 130 (the measurement mode), the illuminance of the illumination light is lower (or the illumination light is extinguished) than in the mode (the normal observation mode) It can be done. Thereby, in the endoscope system 10 which concerns on this embodiment, an image whose diffraction spot is clear can be imaged, and it can measure correctly. The degree to which the illuminance of the illumination light is lowered when imaging the diffraction spot may be set according to the type, size, brightness, etc. of the subject, and the illumination light may be turned off as necessary.

<Measurement of distance between diffraction spots>
Next, based on the image acquired in step S100, the image processing unit 204 (measuring unit, calculating unit) measures the interval D3 of the diffraction spots DS1 (step S110; measuring step). The interval D3 of the diffraction spot DS1 corresponds to the number of pixels on the image forming surface of the imaging device 134. In addition, an interval (for example, an interval near the center of the image forming surface) in a specific part of the plurality of diffraction spots DS1 may be measured.

  In an endoscope system, in general, the imaging angle of view of the imaging lens is wide, and when a diffraction spot is photographed by such an imaging lens, the distance between the diffraction spots in the photographed image (corresponding to the number of pixels on the imaging surface of the imaging device) Changes with the image height (the distance from the center of the imaging surface) of the diffraction spot on the imaging surface of the imaging device. Specifically, when the imaging angle of view of the imaging lens is wide, even if the distance to the object does not change, as the image height increases (that is, as it approaches the periphery of the imaging element), the diffraction spot on the imaging surface The distance between Therefore, if the relationship between the distance between the diffraction spots on the imaging surface of the imaging device and the distance to the object is not dependent on the image height of the diffraction spots, the distance between the diffraction spots (number of pixels in the peripheral portion of the imaging device) ) Is measured shorter than the actual, and the distance to the subject is also calculated shorter than the actual, and as a result, two-dimensional and three-dimensional information of the subject can not be calculated accurately. Therefore, in the endoscope system 10 of the present embodiment, the relationship between the distance between the diffraction spot on the imaging surface of the imaging device 134 and the distance to the object differs depending on the image height of the diffraction spot on the imaging surface ( For example, as the image height of the diffraction spot is higher, the distance to the object corresponding to the same interval (the number of pixels) of the diffraction spot is measured in advance and stored in the memory 212.

  The aspect of storage of the relationship described above may employ various aspects such as a table format, a function format, and the like. Thereby, in the endoscope system 10 according to the present embodiment, even if the imaging angle of view of the imaging lens 132 is wide, the distance between the diffraction spots can be accurately measured. As a result, the distance to the object or the object Two-dimensional and three-dimensional information can be accurately calculated (described later). The relationship stored in the memory 212 differs depending on the shooting angle of view of the imaging lens 132 (for example, the wider the shooting angle of view of the imaging lens 132, the more the same interval (number of pixels) at the same image height). (The distance to the subject to be measured may be long).

  In addition, the relationship between the distance between the diffraction spots and the distance to the object is measured and stored for a partial area (for example, the central part) of the imaging surface, and the distance between the diffraction spots in such partial areas is The distance to the object or the two-dimensional or three-dimensional information of the object may be calculated based on the measurement.

  The measurement of the distance between diffraction spots in step S110 is performed using an image generated by the pixel signal of the pixel in which the color filter of the filter color of red (R) color is disposed. Here, the relationship between the wavelength and the sensitivity in the color filter of each color (red, green, blue) disposed in each pixel of the imaging device 134 is as shown in FIG. 11 and is emitted from the laser light source module 502. The laser beam is a red laser beam with a wavelength of 670 nm. That is, the measurement of the distance between the diffraction spots is performed on an image generated by an image signal of a pixel in which a red color filter having the highest sensitivity to the wavelength of the laser light is arranged among the (red, green and blue) color filters. It is done based on. Thereby, in the endoscope system 10 which concerns on this embodiment, a diffraction spot can acquire a clear image, and it can measure correctly.

<Calculation of the distance to the subject>
When the distance between the diffraction spots is measured in step S110, the direction and distance to the object are calculated based on the measurement result (step S120; calculation step). This process is performed based on the relationship between the distance (number of pixels) of the diffraction spot on the imaging surface of the imaging device 134 and the distance to the object, which is measured in advance and stored in the memory 212. In step S120, specifically, as shown in FIG. 12, the direction (α, β) and the distance (r) of the diffraction spot DS1 to be measured are calculated. In FIG. 12, the center of the imaging plane of the imaging device 134 is the origin O of the coordinate system, the Z axis is the direction orthogonal to the imaging plane, and the X and Y axes are the directions orthogonal to each other in the imaging plane. it can.

<Two-dimensional information and three-dimensional information of subject>
When the direction and distance to the subject (the diffraction spot DS1 to be measured) are calculated in step S120, two-dimensional information or three-dimensional information of the subject is calculated based on the calculated direction and distance (step S130; measurement) Process). As the two-dimensional information and three-dimensional information of the object, the shape in the two-dimensional space (XY plane in FIG. 12) or in the three-dimensional space (XYZ space in FIG. 12) of the object (or the measurement target portion) The size, area, etc. can be calculated. The conversion from (α, β, r) to (X, Y, Z) can be performed by the following equations (1) to (3), and (X, Y, Z) at each point of the subject The shape, size, area, etc. can be calculated from the coordinates.

X = r × cos α × cos β (1)
Y = r × cos α × sin β (2)
Z = r × sin α (3)
Thus, for example, when the user of the endoscope system 10 designates a desired area (for example, the tumor tm in FIG. 10) on the monitor 400 by operating the operation unit 208 or the like, the size of the designated area is calculated It can be displayed on a monitor.

  As described above, in the endoscope system 10 according to the first embodiment, the distance to the object and the two-dimensional and three-dimensional information of the object can be accurately calculated regardless of the distance to the object and the exposure condition. , Can be measured.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the plurality of spot lights are generated using the diffraction grating 512 in which the protrusions 512A are formed in a two-dimensional shape, but in the second embodiment, a plurality of ones using the one-dimensional diffraction grating Generate spot light. The configuration of the second embodiment is the same as that of the first embodiment except for the diffraction grating, so the detailed description will be omitted.

  FIG. 13A is a front view showing a diffraction grating 514 according to the second embodiment, and FIG. 13B is a side view of the diffraction grating 514. As shown in FIG. As shown in FIGS. 13A and 13B, in the diffraction grating 514, protrusions 514A having a one-dimensional shape (linear shape) are formed with a period P2, and a plurality of spot lights are generated by these protrusions 514A. Ru. In the second embodiment, a laser head 515 is configured to include such a diffraction grating 514, and a laser module 520 is configured to include the laser head 515 (see FIG. 14).

Here, the relationship between the distance between the protrusions 514A and the spread of the spot light is illustrated. Assuming that the wavelength λ of the laser light is 670 nm and the period P2 of the protrusions 514A is 2 μm (500 per 1 mm) as in the first embodiment, the irradiation direction of the spot light is θ on the surface on which the protrusions 514A are formed. The angle from the vertical direction is represented by θ = sin ⁻¹ (λ / P 2), which is approximately 19.6 (deg).

  FIGS. 15A and 15B are diagrams showing a plurality of diffraction spots DS2 formed by the diffraction grating 514 in the one-dimensional direction (linear direction). FIG. 15A shows a state in which the distance to the object is far, and the distance between the diffraction spots DS2 is wide. On the other hand, FIG. 15 (b) shows a state in which the distance to the subject is closer than in FIG. 15 (a), and the distance between the diffraction spots DS2 is narrower than in FIG. 15 (a).

  FIG. 16 is a view showing a state in which the diffraction spots DS2 (the interval is D4) shown in FIGS. 15 (a) and 15 (b) are formed on a subject (a portion of a tumor tm). Similar to the first embodiment, the distance to the object, the two-dimensional information of the object, and the three-dimensional information can be accurately calculated and measured based on the diffraction spot DS2. In the second embodiment, as shown in FIG. 16, the diffraction spot DS2 is formed in a one-dimensional shape (linear shape), but the bending portion 114 is curved vertically and horizontally by the operation of the hand operation portion 102 to make the tip rigid. By changing the orientation of the portion 116 (diffraction grating 514) so that the diffraction spot DS2 is formed in a direction different from that of FIG. 16 (for example, the direction orthogonal to the direction in FIG. 16), information about such different directions You can get

Third Embodiment
Next, a third embodiment of the present invention will be described. In the first embodiment described above, a plurality of spot lights are generated using the diffraction grating 512 in which the protrusions 512A are formed in a two-dimensional shape, but in the third embodiment, it is the same as the second embodiment. A plurality of spot lights are generated by a laser module using a plurality of one-dimensional diffraction gratings. The configuration of the third embodiment is the same as that of the first embodiment except for the laser module, and therefore detailed description will be omitted.

  FIG. 17 is a diagram showing the configuration of a laser module 530 according to the third embodiment. The laser module 530 includes a laser light source module 502 and an optical fiber 504 similar to those of the first embodiment, and also includes a ferrule 508 and a GRIN lens 510 as in the first embodiment. In the second embodiment, diffraction gratings 516 and 518 are used instead of the diffraction grating 512 (see FIGS. 4 and 5) according to the first embodiment.

  18 (a) and 18 (b) are front and side views, respectively, of the diffraction grating 516 mounted on the distal end side of the laser head 532. FIGS. 19 (a) and 19 (b) are proximal end sides of the laser head 532. FIG. 16 is a front view and a side view of the diffraction grating 518 attached to the A plurality of one-dimensional protrusions 516A, 518A are respectively formed on the diffraction gratings 516, 518. In the laser head 532, the diffraction gratings 516, 518 are arranged such that the directions of the protrusions 516A, 518A are orthogonal to each other. . The ferrule 508, the GRIN lens 510, and the diffraction gratings 516 and 518 are housed in a housing 509 to constitute a laser head 532 (FIG. 17).

  Under the above configuration, in the third embodiment as well as in the first and second embodiments, the distance to the object, the two-dimensional information of the object, and the three-dimensional information can be accurately calculated and measured. it can.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. In the first to third embodiments described above, the ferrule, the GRIN lens, and the diffraction grating are housed in the housing, but in the fourth embodiment, the ferrule 508, GRIN is used without using the housing as shown in FIG. The lens 510 and the diffraction grating 512 are bonded with a transparent adhesive to constitute a laser head 542, and the laser head 54 is included to constitute a laser module 540. In the fourth embodiment, since the housing is not used, the diameter of the laser head 542 can be reduced. In FIG. 20, members given the same reference numerals as those of the laser module 500 according to the first embodiment have the same configuration as that of the first embodiment.

  Also in the fourth embodiment of the configuration described above, the distance to the object, the two-dimensional information of the object, and the three-dimensional information can be accurately calculated and measured in the same manner as in the first to third embodiments. it can.

<Modification>
In the first to fourth embodiments described above, the case of measuring the distance between diffraction spots based on an image generated by an image signal of a pixel provided with a red color filter is described, but the present invention In the above, the distance measurement of the diffraction spot may be performed by an image generated by an image signal of a pixel provided with a color filter of any one or two colors among (red, green and blue), , Green, and blue) may be performed by color images generated by image signals of all three colors.

  Moreover, although the case where red laser light is used was described in the first to fourth embodiments described above, the wavelength of the laser light is limited to red in the measurement apparatus, endoscope system, and measurement method of the present invention. It is possible to use laser beams of different wavelengths depending on the type of object and the purpose of measurement.

  The measurement apparatus, the endoscope system, and the measurement method of the present invention can be applied not only to the measurement of an object that is a living body, but also to measurement of piping or other non-living objects. Moreover, the measuring device, the endoscope system, and the measuring method of the present invention are applicable not only to the endoscope but also to measuring the dimensions and shapes of industrial parts and products.

  Although the example of the present invention has been described above, the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 10 Endoscope system 100 Endoscope apparatus 102 Hand operation part 116 Tip hard part 126 Forceps opening 130 Imaging optical system 132 Imaging lens 134 Imaging element 200 Inside An endoscope processor, 300, a light source device, 350, a light source control unit, 500, 520, 530, 540, a laser module, 502, a laser light source module, 504, an optical fiber, 506, 515, 532, 542, a laser head, 508, a ferrule 509: housing 510: GRIN lens 512, 514, 516, 518: diffraction grating 512A, 514A, 516A, 518A: projection, DS1, DS2: diffraction spot

Claims (12)

A laser light source for emitting laser light;
A collimator for emitting the emitted laser beam as a parallel luminous flux;
A diffraction grating that generates a plurality of spot lights from a light beam emitted by the collimator , wherein the diffraction grating generates a plurality of spot lights having a predetermined cycle in a two-dimensional direction as the plurality of spot lights ;
An imaging unit configured to acquire an image of a plurality of diffraction spots formed on a subject by the plurality of spot lights through an imaging element;
A measurement unit configured to measure an interval of the plurality of diffraction spots on the imaging surface of the imaging device based on the acquired image;
An endoscope system comprising: a measurement unit configured to calculate a distance to the subject based on the intervals of the plurality of measured diffraction spots ;
A distal end hard portion, a curved portion connected to the proximal end side of the distal end hard portion, and a flexible portion connected to the proximal end side of the curved portion. An endoscope having an insertion portion having an operation portion connected to the proximal end side of the insertion portion;
An endoscope system, wherein the diffraction grating and an imaging lens for forming an optical image of the plurality of diffraction spots on the imaging element are provided on the end surface of the distal end hard portion . The said calculation part calculates the distance to the said object based on the relationship of the space | interval of these diffraction spots in the said imaging surface, and the distance to the said object memorize | stored beforehand. Endoscope system . The endoscope system according to claim 2, wherein the prestored relationship differs depending on the image heights of the plurality of diffraction spots on the imaging surface. In the previously stored relationship, as the image heights of the plurality of diffraction spots are higher, the distance to the object corresponding to the same distance between the plurality of diffraction spots on the imaging surface is longer. Endoscope system as described. The imaging device is a color imaging device including a plurality of pixels composed of a plurality of light receiving elements arranged in a two-dimensional array, and a color filter of a plurality of filter colors disposed on the plurality of pixels.
The measurement unit is configured to generate a plurality of diffraction spots based on an image generated by an image signal of a pixel in which a color filter having the highest filter sensitivity to the wavelength of the laser light among the plurality of filter colors is disposed. Measure the interval,
The endoscope system according to any one of claims 1 to 4 . The endoscope system according to any one of claims 1 to 5 , wherein the calculation unit calculates two-dimensional information or three-dimensional information of the subject based on the calculated distance to the subject. The endoscope system according to any one of claims 1 to 6 , further comprising: an optical fiber for guiding the laser light from the laser light source to the collimator, wherein the optical fiber propagates the laser light in a single transverse mode. . The endoscope system according to any one of claims 1 to 7 , wherein the collimator is a graded index type lens in which the refractive index is the highest at the optical axis and decreases toward the radially outer side. The endoscope system according to any one of claims 1 to 8 , wherein a module including an assembly of the diffraction grating and the collimator is provided in the distal end hard portion. The endoscope system according to claim 9 , wherein a conduit communicating with the forceps port opened in the distal end hard portion is provided in the insertion portion, and the module is inserted through the conduit in a removable manner. An illumination light source that emits illumination light; and a control unit that controls the illuminance of the illumination light,
In the measurement mode in which the control unit acquires the images of the plurality of diffraction spots by the imaging unit, the illuminance of the illumination light is higher than that in the normal observation mode in which the subject is irradiated with the illumination light to observe the subject The endoscope system according to any one of claims 1 to 10 which lowers. Operation of a measuring apparatus comprising: a laser light source for emitting a laser beam; a collimator for emitting the emitted laser beam as a parallel light beam; and a diffraction grating for generating a plurality of spot lights from the light beam emitted by the collimator Method,
An imaging step of acquiring images of a plurality of diffraction spots formed on a subject by the plurality of spot lights;
Measuring the distance between the plurality of diffraction spots based on the acquired image;
Calculating the distance to the subject based on the measured intervals of the plurality of diffraction spots;
Method of operating a measuring device comprising

Images